Medical Policy: 07.01.62
Original Effective Date: January 2014
Reviewed: October 2016
Revised: October 2016
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This Medical Policy document describes the status of medical technology at the time the document was developed. Since that time, new technology may have emerged or new medical literature may have been published. This Medical Policy will be reviewed regularly and be updated as scientific and medical literature becomes available.
Gastric electrical stimulation (GES) is performed using an implantable device designed to treat chronic, refractorynausea and vomiting secondary to gastroparesis of diabetic, idiopathic, or postsurgical etiology. Gastroparesis is often associated with diabetes, it is also found in chronic pseudo-obstruction, connective tissue disorders, Parkinson disease and psychological pathology. Gastric electrical stimulation has also been investigated as a treatment of obesity. The device may also be referred to as a gastric pacemaker.
Gastric electrical stimulation has been investigated primarily as a treatment for gastroparesis that helps control the chronic nausea and vomiting associated with gastroparesis by stimulating the smooth muscles of the lower stomach. Currently available devices consist of a pulse generator, which can be programmed to provide electrical stimulation at different frequencies connected to intramuscular stomach leads that are implanted during laparoscopy or open laparotomy.
Gastroparesis is defined as delayed gastric emptying of solids in the absence of mechanical obstruction. It can frequently result from longstanding diabetes mellitus and vagal nerve injury, or can be idiopathic in nature. Gastroparesis leads to postprandial nausea and vomiting, bloating, early satiety and discomfort. In severe cases, nausea and vomiting may cause weight loss, dehydration, electrolyte disturbances and malnutrition due to inadequate caloric and fluid intake.
Idiopathic – idiopathic gastroparesis may be the most common form of gastroparesis. It is estimated that no detectable underlying abnormality is found in approximately one-half of patients with delayed gastric emptying.
Diabetes Mellitus – Diabetes mellitus (DM) is the most frequently recognized systemic disease associated with gastroparesis. Gastrointestinal complications of diabetes typically occur in patients who have had the disorder for more than five years. Patients with diabetes mellitus have abnormalities at several levels in the process of gastric emptying, including abnormal postprandial proximal gastric accommodation and contraction, and difficulties with antral motor function. These abnormalities are primarily due to autonomic dysfunction or abnormal intrinsic nervous system.
Hyperglycemia (blood glucose > 200 mg/dL) may also contribute to delayed gastric emptying.
Post-Surgical – previous gastric and thoracic surgery can result in gastric stasis due to intended or accidental injury to the vagus nerve.
The evaluation of gastroparesis is to exclude mechanical obstruction and establish the diagnosis of gastroparesis by an assessment of gastric motility. If there is no evidence of mechanical obstruction on imaging or upper endoscopy, scintigraphy is typically performed to document the presence of delayed gastric emptying. Scintigraphy measures the motor function of the stomach by quantifying the emptying of a physiologic caloric meal. The technique involves incorporating a radioisotope tracer into a standard meal and tracking its passage through the stomach using a gamma camera. Images are typically gathered at 1, 2, 3, and 4 hours.
Delayed gastric emptying is defined as gastric retention of > 10 percent at 4 hours and/or > 60 percent at two hours when using a standard low fat diet. Although the severity of symptoms do not always correlate with the rate of gastric emptying, delayed gastric emptying has been classified based on the extent of gastric retention on scintigraphy at four hours into the following:
Primary medical management for gastroparesis includes dietary modification and pharmacologic therapy with prokinetic agents such as metoclopramide, macrolide antibiotics such as erythromycin and antiemetic agents such as granisetron or ondansetron. Patients refractory to treatment are difficult to manage. Treatment may involve changing or combining medications; placement of gastrostomy or jejunostomy tube for enteral feedings, or in severe cases, total parenteral nutrition (TPN) for brief periods. Some patients, however, remain refractory to gastroparesis treatment.
Currently, only one gastric electrical stimulator has received approval from the U.S. Food and Drug Administration (FDA), the Enterra™ Therapy System, manufactured by Medtronic and it was cleared by the FDA as a humanitarian use device. This system delivers a high frequency (12 cycles per minute), low energy stimulation to the stomach. The FDA labeling for Enterra™ Therapy System indicates the use of this system for the treatment of chronic, intractable (drug refractory) nausea and vomiting secondary to gastroparesis of diabetic or idiopathic etiology.
In rare instances, certain medical devices intended to be used for humanitarian purposes are evaluated by the US Food and Drug Administration (FDA) through the Humanitarian Device Exemption (HDE) process. The FDA’s humanitarian use device (HUD) designation permits the use of certain medical devices when there is no comparable device available to treat or diagnose a disease or condition affecting fewer than 4,000 individuals annually. Since clinical investigation demonstrating the device's efficacy is not feasible (given the low prevalence of the disease in the population), an HDE grants manufacturers an exemption to the usual premarket approval process and allows marketing of the device only for the FDA-labeled HDE indication(s).
Under FDA requirements, an HUD may only be used after institutional review board (IRB) approval has been obtained for the use of the device in accordance with the FDA-labeled indication(s) under the HDE.
Gastric electrical stimulation (GES) has also been investigated as a treatment of obesity as a technique to increase a feeling of satiety with subsequent reduced food intake and weight loss. The exact mechanisms resulting in changes in eating behavior are uncertain but may be related to neuro-hormonal modulation and/or stomach muscle stimulation. Currently there are no GES devices approved by the U.S. Food and Drug Administration for the treatment of obesity. Based on review of the medical literature which includes 1 published randomized study (SHAPE trial), this trial did not show any improvement in weight loss with GES compared with sham stimulation. The evidence is insufficient to determine the effects of this technology on health outcomes.
Based on the humanitarian device exemption indication granted by the U.S. Food and Drug Administration (FDA),gastric electrical stimulation (GES) may be a safe and effective option for those patients with chronic, intractable nausea and vomiting secondary to gastroparesis of diabetic or idiopathic etiology who have failed all other treatments. The use of GES for the treatment of all other indications including obesity remains unproven, optimal patient selection criteria, electrode position, lead number and stimulation patterns have not yet been determined. Additional well designed studies are not needed to demonstrate the safety and effectiveness of GES for these indications.
The American College of Gastroenterology published a clinical practice guideline on the management of gastroparesis in 2013. The recommendations for these guidelines were based on review of the evidence base through 2011. The evidence on GES consisted of 2 randomized crossover trials and the case series. The recommendation for GES was that “Gastric electrical stimulation may be considered for compassionate treatment in patients with refractory symptoms, particularly nausea and vomiting. Symptom severity and gastric emptying have been shown to improve in patients with diabetic gastroporesis (DG), but not in patients with idiopathic gastroparesis (IG) or postsurgical gastroparesis (PSG). (Conditional recommendation (there is uncertainty about trade-offs), moderate level of evidence (further research would be likely to have an impact on the confidence in the estimate of effect)
In 2014, the National Institute for Health and Care Excellence issued guidelines on gastroelectrical stimulation for gastroparesis that made the following recommendation:
Currently, only the Gastric Electrical Stimulator (GES) system (now called Enterra™ Therapy System; Medtronic, Minneapolis, MN) has been approved by the U.S. Food and Drug Administration (FDA; see note below). The GES system consists of 4 components: the implanted pulse generator, 2 unipolar intramuscular stomach leads, the stimulator programmer, and the memory cartridge. With the exception of the intramuscular leads, all other components have been used in other implantable neurologic stimulators, such as spinal cord or sacral nerve stimulation. The intramuscular stomach leads are implanted either laparoscopically or during a laparotomy and are connected to the pulse generator, which is implanted in a subcutaneous pocket. The programmer sets the stimulation parameters, which are typically set at an “on” time of 0.1 second alternating with an “off” time of 5.0 second.
Note: In March 2000, the GES system was approved by FDA through a humanitarian device exemption (HDE Approval H990014). This regulatory category was established in 1996 and only applies to devices intended to benefit fewer than 4000 patients. The approval process is similar to that of a premarket approval application (PMA) but is exempt from the effectiveness requirements of a PMA. Thus the application is not required to include results of scientifically valid clinical investigations but must contain sufficient information for FDA to determine that the device does not pose unreasonable or significant risk of illness or injury. A humanitarian use device may only be used in facilities that have an institutional review board to supervise clinical testing of the device.
See also Humanitarian Use Devices medical policy 10.01.14
See also Vagus Nerve Stimulation (VNS) medical policy 07.01.60
Gastric electrical stimulation (eg, Enterra™ Therapy) may be considered medically necessary for the humanitarian device exemption (HDE) indication granted by the US Food and Drug Administration (FDA) for the treatment of chronic intractable (drug refractory) nausea and vomiting secondary to gastroparesis of diabetic or idiopathic etiology when the following criteria are met:
An institutional review board (IRB) must approve the use of gastric electrical stimulation for the treatment of gastroparesis to ensure that it will be used in accordance with the HDE indication(s) granted by the FDA. Documentation of IRB approval may be requested to ensure compliance with such indications.
Gastric electrical stimulation and gastric pacing would be considered investigational for all other indications, including but not limited to the following because the safety and effectiveness of this service cannot be established by review of the available published medical literature:
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